#include <bits/stdc++.h>
#include <atcoder/all>
typedef long long ll;
typedef long double lb;
using namespace std;
using namespace atcoder;
#define all(x) (x).begin(), (x).end()
#define OVERLOAD_REP(_1, _2, _3, name, ...) name
#define REP1(i, n) for (auto i = std::decay_t<decltype(n)>{}; (i) != (n); ++(i))
#define REP2(i, l, r) for (auto i = (l); (i) != (r); ++(i))
#define rep(...) OVERLOAD_REP(__VA_ARGS__, REP2, REP1)(__VA_ARGS__)
template<class T> bool chmin(T& a, const T& b){if(a > b){a = b; return 1;} return 0;}
template<class T> bool chmax(T& a, const T& b){if(a < b){a = b; return 1;} return 0;}
const ll INF = 1000000000000000000; // 10^18
const ll mod = 998244353;

int main(){
    ll n;
    string a;
    cin >> n >> a;
    vector<ll> v;
    for (int l = 0; l < n;) {
        int r = l + 1;
        for (; r < n && a[l] == a[r]; r++) {};
        v.push_back(r-l);
        l = r;
    }
    ll ans = 1;
    if(a[0] == '0' && a[a.size()-1] == '1'){
        for(ll i = 0;i < v.size();i+=2){
            ll tmp = 0;
            tmp = (v[i] + v[i+1] + 1) % mod;
            ans *= tmp;
            ans %= mod;
        }
    }else if(a[0] == '0' && a[a.size()-1] == '0'){
        for(ll i = 0;i < v.size()-1;i+=2){
            ll tmp = 0;
            tmp = (v[i] + v[i+1] + 1) % mod;
            ans *= tmp;
            ans %= mod;
        }
    }else if(a[0] == '1' && a[a.size()-1] == '1'){
        for(ll i = 1;i < v.size()-1;i+=2){
            ll tmp = 0;
            tmp = (v[i] + v[i+1] + 1) % mod;
            ans *= tmp;
            ans %= mod;
        }
    }else if(a[0] == '1' && a[a.size()-1] == '0'){
        for(ll i = 1;i < v.size()-2;i+=2){
            ll tmp = 0;
            tmp = (v[i] + v[i+1] + 1) % mod;
            ans *= tmp;
            ans %= mod;
        }
    }
    cout << ans << endl;
    return 0;
}